netwinz cyclic redundancy check guide

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netwinz CYCLIC REDUNDANCY CHECK Introduction: A cyclic redundancy check (CRC) is an error-detecting code designed to detect accidental changes to raw computer data, and is commonly used in digital networks and storage devices such as hard disk drives. A CRC-enabled device calculates a short, fixed-length binary sequence, known as the check value or improperly the CRC, for each block of data to be sent or stored and appends it to the data, forming a codeword. When a codeword is received or read, the device either compares its check value with one freshly calculated from the data block, or equivalently, performs a CRC on the whole codeword and compares the resulting check value with an expected residue constant. If the check values do not match, then the block contains a data error and the device may take corrective action such as rereading or requesting the block be sent again, otherwise the data is assumed to be error-free. netwinz Guide

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DESCRIPTION

A cyclic redundancy check (CRC) is an error-detecting code designed to detect accidental changes to raw computer data, and is commonly used in digital networks and storage devices such as hard disk drives. A CRC-enabled device calculates a short, fixed-length binary sequence, known as the check value or improperly the CRC, for each block of data to be sent or stored and appends it to the data, forming a codeword. When a codeword is received or read, the device either compares its check value with one freshly calculated from the data block, or equivalently, performs a CRC on the whole codeword and compares the resulting check value with an expected residue constant. If the check values do not match, then the block contains a data error and the device may take corrective action such as rereading or requesting the block be sent again, otherwise the data is assumed to be error-free.HOW TO CONDUCT THE EXPERIMENT:TRANSMITTER:1. Click on Physical Layer on the Main Window and Then Select CRC Module from the Modules displayed in the centre of the window.CRC Window will open up as shown in SNAPSHOT-1. SNAPSHOT-12. Enter the “IP Address” of the computer to which you intend to send data.3. Enter the “Text” that you intend to send . 4. Click on Form Frame button.The Frame will be displayed in the table below.Also the CRC value in decimal is displayed in the textbox below the table.Have a look at the frame and CRC value and reconfirm using the CRC calculation algorithm. 5. You can Change the Data in the frame by directly editing the table to cause CRC Error.6. Click on the “SEND FRAME” button to send the Frame to the destination IP.Use Loop back Address “127.0.0.1” to send the Frame to the same computer.RECEIVER:In the Receiver Window, the Frame is displayed in the table as soon as the frame is received.1. Click on “CHECK CRC” button to calculate CRC on the receiver side and also to check if the calculated CRC and received CRC match.Both Calculated CRC and Received CRC are Displayed in the receiver and the color is either green to signal a match or Red to signal disparity.SNAPSHOT-2 Shows a match and SNAPSHOT-2 Shows Disparity. SNAPSHOT-2 SNAPSHOT-3

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Page 1: netwinz Cyclic Redundancy Check Guide

netwinz

CYCLIC REDUNDANCY CHECK

Introduction:

A cyclic redundancy check (CRC) is an error-detecting code designed to detect

accidental changes to raw computer data, and is commonly used in digital

networks and storage devices such as hard disk drives. A CRC-enabled device

calculates a short, fixed-length binary sequence, known as the check value or

improperly the CRC, for each block of data to be sent or stored and appends it to

the data, forming a codeword. When a codeword is received or read, the device

either compares its check value with one freshly calculated from the data block,

or equivalently, performs a CRC on the whole codeword and compares the

resulting check value with an expected residue constant. If the check values do

not match, then the block contains a data error and the device may take

corrective action such as rereading or requesting the block be sent again,

otherwise the data is assumed to be error-free.

netwinz Guide

Page 2: netwinz Cyclic Redundancy Check Guide

HOW TO CONDUCT THE EXPERIMENT:

TRANSMITTER:

1. Click on Physical Layer on the Main Window and Then Select CRC Module

from the Modules displayed in the centre of the window.

CRC Window will open up as shown in SNAPSHOT-1.

SNAPSHOT-1

2. Enter the “IP Address” of the computer to which you intend to send data.

3. Enter the “Text” that you intend to send .

4. Click on Form Frame button.

The Frame will be displayed in the table below.

Also the CRC value in decimal is displayed in the textbox below the table.

Have a look at the frame and CRC value and reconfirm using the CRC calculation

algorithm.

Page 3: netwinz Cyclic Redundancy Check Guide

5. You can Change the Data in the frame by directly editing the table to cause

CRC Error.

6. Click on the “SEND FRAME” button to send the Frame to the destination IP.

Use Loop back Address “127.0.0.1” to send the Frame to the same computer.

RECEIVER:

In the Receiver Window, the Frame is displayed in the table as soon as the frame

is received.

1. Click on “CHECK CRC” button to calculate CRC on the receiver side and also

to check if the calculated CRC and received CRC match.

Both Calculated CRC and Received CRC are Displayed in the receiver and the color

is either green to signal a match or Red to signal disparity.

SNAPSHOT-2 Shows a match and SNAPSHOT-2 Shows Disparity.

SNAPSHOT-2

Page 4: netwinz Cyclic Redundancy Check Guide

SNAPSHOT-3

Transmitter and Receiver Messages are Displayed in the “Message Window” on

the extreme right.

Reset Button:

Click On “RESET BUTTON” to reset all the controls to initial values.

Click on “HELP BUTTON” to Open CRC Manual.

Click on “EXIT BUTTON” To Close CRC Window.

Copyright © 2011 Emblitz Technologies Pvt Ltd. All rights reserved. www.netwinz.com